1. Field of the Invention
The present invention relates to an imaging system and an imaging method, particularly relates to a monitoring system and a monitoring method, and more particularly relates to a monitoring system and a monitoring method for effectively reducing a data amount of a picked-up image.
2. Description of the Related Art
In recent years, monitoring systems using imaging systems have been disposed in various places and used for detection of intruders.
A monitoring system is required to acquire an image of a wide region and acquire an image of sufficient image quality for specifying a person detected in an imaging region at the same time for the purpose of monitoring the action of the person detected in the imaging region.
Japanese Patent Application Laid-Open No. 2007-243660 proposes a system and a method in which a whole monitoring region is read out in a low resolution, the low-resolution image is analyzed, the characteristic region in the monitoring region is specified from the result, and the region is read out with a high resolution.
Further, Japanese Patent Application Laid-Open No. 2007-110289 suggests a system and a method in which a marked region and an unmarked region are separated in the images in a monitoring region, and the image of only the marked region is acquired in a high resolution.
The invention described in Japanese Patent Application Laid-Open No. 2007-243660 adopts the method in which the inside of an imaging region is photographed in a low resolution, and only when a human figure or the like is detected within the imaging region, the region in which the human figure is detected is photographed in a high resolution. However, when the monitoring range becomes wider, if the image is acquired in a resolution sufficient for detecting a human figure, the data amount becomes enormous, and if the resolution is reduced to suppress the data amount, detection of a human figure itself is highly likely to become difficult. Further, apart from the above described problem, an increase in system load due to useless image data is unavoidable, since information such as a background which does not necessarily need monitoring continues to be acquired.
The invention described in Japanese Patent Application Laid-Open No. 2007-110289 adopts the method in which only a marked region is read out in a high resolution, and the other region is read out in a low resolution. In this method, a marked region is always read out in a high resolution, but in the case of monitoring, even the marked region does not always have to be read out in a high resolution, and only when an object to be monitored is present in the marked region, the marked region has to be read out with a high resolution. Specifically, from the viewpoint of the system load, this method is inefficient.
From the above, in the conventional monitoring systems and monitoring methods, enhancement in ability of detection of a monitoring object such as a human figure in wide-range monitoring, and suppression of increase in system load caused by processing of an acquired image have not been able to be made compatible. This is not limited to the monitoring systems, and in ordinary digital cameras and the like, the similar problem is likely to exist from the viewpoint of enhancement in speed of processing at the time of imaging an object after capturing the object.
An object of the present invention is to provide an imaging system and method which can make enhancement in ability of detection of a monitoring object such as a human figure in wide-range monitoring, and suppression of increase in system load caused by processing of a picked-up image compatible.